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Articles 175801 - 175830 of 197997

Full-Text Articles in Engineering

Proton Diffusion In Nickel Hydroxide Films: Measurement Of The Diffusion Coefficient As A Function Of State Of Charge, Sathya Motupally, Christopher C. Streinz, John W. Weidner Jan 1995

Proton Diffusion In Nickel Hydroxide Films: Measurement Of The Diffusion Coefficient As A Function Of State Of Charge, Sathya Motupally, Christopher C. Streinz, John W. Weidner

Faculty Publications

Electrochemical impedance spectroscopy (EIS) was used to measure the solid-state diffusion coefficient of protons in nickel hydroxide films at room temperature as a function of state of charge (SOC). A model for the complex faradaic impedance of the nickel hydroxide active material is presented and used to extract the diffusion coefficient of protons from the EIS data. Impedance data over a range of frequencies can be used to extract a constant diffusion coefficient without the knowledge of the initial mobile proton concentration or the form of the charge-transfer kinetic expression. The proton diffusion coefficient is a strong function of SOC …

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The Effect Of Temperature And Ethanol On The Deposition Of Nickel Hydroxide Films, Christopher C. Streinz, Sathya Motupally, John W. Weidner Jan 1995

The Effect Of Temperature And Ethanol On The Deposition Of Nickel Hydroxide Films, Christopher C. Streinz, Sathya Motupally, John W. Weidner

Faculty Publications

The objective of this work was to determine the effect of the temperature and the ethanol content of the Ni(NO3)2 solution on: (i) the efficiency of electrochemical deposition of nickel hydroxide; and (ii) the molecular weight of the deposited film. An electrochemical quartz crystal nanobalance (EQCN) was used to measure the mass of films electrochemically deposited from Ni(NO3)2 solutions and constant current discharges were used to determine the electrochemical capacity of the films. The data indicates that increasing the temperature increases both the efficiency of the deposition reaction and the …

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Electrowinning Of Non-Noble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes I. Theoretical, Mahmoud M. Saleh, John W. Weidner, Badr G. Ateya Jan 1995

Electrowinning Of Non-Noble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes I. Theoretical, Mahmoud M. Saleh, John W. Weidner, Badr G. Ateya

Faculty Publications

A mathematical model is developed to simulate the electrowinning of non-noble metals (e.g., Zn, Cr) within flow-through porous electrodes under the conditions of simultaneous evolution of hydrogen gas bubbles. The results of the model are presented as a function of several dimensionless groups representing kinetics, mass transfer, ohmic resistance, and gas bubbles. These coupled, nonlinear effects are investigated by examining the distributions of the metal reduction and hydrogen evolution currents, coulombic efficiency of the metal electrowinning reaction, and gas void fractions under a series of limiting conditions. The gas bubbles accentuate the nonuniform distribution of the potential and …

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Applying Neural Networks To Find The Minimum-Cost Coverage Of A Boolean Function, Pong P. Chu Jan 1995

Applying Neural Networks To Find The Minimum-Cost Coverage Of A Boolean Function, Pong P. Chu

Electrical and Computer Engineering Faculty Publications

To find a minimal expression of a boolean function includes a step to select the minimum cost cover from a set of implicants. Since the selection process is an NP-complete problem, to find an optimal solution is impractical for large input data size. Neural network approach is used to solve this problem. We first formalize the problem, and then define an ''energy function'' and map it to a modified Hopfield network, which will automatically search for the minima. Simulation of simple examples shows the proposed neural network can obtain good solutions most of the time.

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Nonlinear Finite Element Micromechanic Analysis Of Thermoplastic Composite Of Recycled High Density Polyethylene Reinforced With Short Glass Fibers, Qiming Lou Jan 1995

Nonlinear Finite Element Micromechanic Analysis Of Thermoplastic Composite Of Recycled High Density Polyethylene Reinforced With Short Glass Fibers, Qiming Lou

Masters Theses

This thesis studied the nonlinear micromechanic behavior of thermoplastic composite of recycled high density polyethylene (HDPE) reinforced with short glass fibers using finite element method. The composite material was modeled using a micromechanic unit cell to simulate the stress distribution between the plastic matrix and the fiber in the composite. Nonlinear behavior of recycled HDPE and imperfect bonding between the fiber and matrix were investigated. Load-bearing capability of the fiber was evaluated using stress partition ratio (SPR) in the composite models. The effect of fiber aspect ratio on the stress distribution of the composite was studied to optimize the material …

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A General Approach To Boolean Function Decomposition And Its Application In Fpgabased Synthesis, Tadeusz Luba, Henry Selvaraj Jan 1995

A General Approach To Boolean Function Decomposition And Its Application In Fpgabased Synthesis, Tadeusz Luba, Henry Selvaraj

Electrical & Computer Engineering Faculty Research

An effective logic synthesis procedure based on parallel and serial decomposition of a Boolean function is presented in this paper. The decomposition, carried out as the very first step of the .synthesis process, is based on an original representation of the function by a set of r-partitions over the set of minterms. Two different decomposition strategies, namely serial and parallel, are exploited by striking a balance between the two ideas. The presented procedure can be applied to completely or incompletely specified, single- or multiple-output functions and is suitable for different types of FPGAs including XILINX, ACTEL and ALGOTRONIX devices. The …

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Diagnostic And Adaptive Redundant Robotic Planning And Control, Anya Lynn Tascillo Jan 1995

Diagnostic And Adaptive Redundant Robotic Planning And Control, Anya Lynn Tascillo

Graduate Dissertations and Theses

Neural networks and fuzzy logic are combined into a hierarchical structure capable of planning, diagnosis, and control for a redundant, nonlinear robotic system in a real world scenario. Throughout this work levels of this overall approach are demonstrated for a redundant robot and hand combination as it is commanded to approach, grasp, and successfully manipulate objects for a wheelchair-bound user in a crowded, unpredictable environment. Four levels of hierarchy are developed and demonstrated, from the lowest level upward: diagnostic individual motor control, optimal redundant joint allocation for trajectory planning, grasp planning with tip and slip control, and high level task …

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Locally Weighted Polynomial Regression: Parameter Choice And Application To Forecasts Of The Great Salt Lake, Upmanu Lall, Young-Ii Moon, Ken Bosworth Jan 1995

Locally Weighted Polynomial Regression: Parameter Choice And Application To Forecasts Of The Great Salt Lake, Upmanu Lall, Young-Ii Moon, Ken Bosworth

Reports

Relationships between hydrologic variables are often nonlinear. Usually the functional form of such a relationship is not known a priori. A multivariate, nonparametric regression methodology is provided here for approximating the underlying regression function using locally veighted polynomials. Locally weighted polynomials consider the approximation of the target function through a Taylor series expansion of the function in the neighborhood of the point of estimate. Cross validatory procedures for the selection of the size of the neighborhood over which this approximation should take place, and for the order of the local polynomial to use are provided and shown for some simple …

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Optimal Pumping Strategy To Capture Tce Plume At Base Boundary, Norton Afb, California, Richard C. Peralta, A. H. Aly Jan 1995

Optimal Pumping Strategy To Capture Tce Plume At Base Boundary, Norton Afb, California, Richard C. Peralta, A. H. Aly

Civil and Environmental Engineering Faculty Publications

Ground water contaminated by trichloroethylene (TCE) at Norton AFB (NAFB) has reached off-base supply wells. Utah State University (USU) computed an optimal steady pumping strategy to eventually halt off-base migration of TCE exceeding 5 ppb. (A steady pumping strategy is a spatially distributed set of extraction and injection rates.)

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Simplex Algorithm For Optimizing Drainage Design, Majid Ehteshami, Lyman S. Willardson, Richard C. Peralta Jan 1995

Simplex Algorithm For Optimizing Drainage Design, Majid Ehteshami, Lyman S. Willardson, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A methodology and computer model is developed to determine economically optimum closed subsurface drainage systems in irrigated areas. The model maximizes net benefits, by comparing profit driven by crop yield to drain system cost and selects an optimum drain layout. The optimization methodology used, is the SIMPLEX method, Neider and Mead. The SIMPLEX model was linked to the subsurface drainage model DRAINMOD Skaggs [10], and to the surface hydraulic model KINE, Walker and Skogerboe[14]. The selected optimum drainage system maximizes the difference between total revenue, and the total cost of installation, operation and management of a particular drainage system. The …

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Optimal Perennial Groundwater Yield Planning For Complex Nonlinear Aquifers: Methods And Examples, Shu Takahashi, Richard C. Peralta Jan 1995

Optimal Perennial Groundwater Yield Planning For Complex Nonlinear Aquifers: Methods And Examples, Shu Takahashi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Optimal perennial groundwater yield pumping strategies were computed for a complex multilayer aquifer with: (i) confined and unconfined flow, and (ii) many flows typically described by piecewise-linear (nonsmooth) equations. The latter flows account for over 50% of the aquifer discharge from the test area, the eastern shore of the Great Salt Lake in Utah. Normally utilized response matrix (RM) and embedding (EM) simulation/optimization modelling procedures did not converge to optimal solutions for this area; they diverged or oscillated. However, the newly presented linear RM and EM approaches satisfactorily addressed the nonlinearities posed by over 2000 piecewise-linear constraints for evapotranspiration, discharge …

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Stepwise Pumping Approach To Improve Free Phase Light Hydrocarbon Recovery From Unconfined Aquifers, Grant Cooper, Richard C. Peralta, Jagath J. Kaluarachchi Jan 1995

Stepwise Pumping Approach To Improve Free Phase Light Hydrocarbon Recovery From Unconfined Aquifers, Grant Cooper, Richard C. Peralta, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

A stepwise, time-varying pumping approach is developed to improve free phase oil recovery of light non-aqueous phase liquids {LNAPL) from a homogeneous, unconfined aquifer. Stepwise pumping is used to contain the floating oil plume and obtain efficient free oil recovery. The pumping approach is developed using detailed simulations, multiple linear regression and graphical plots. The approach uses ARMOS©, an areal two-dimensional multiphase flow, finite-element simulation model. Systematic simulations of f~ oil area changes to pumping rates are analyzed. Pumping rates are determined that achieve LNAPL plume containment at different times (i.e. 90, 180 and 360 days) for a planning period …

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The Influence Of Pcl 3 On Planarisation And Selectivity Of Inp Regrowth By Atmospheric Pressure Movpe, M. J. Harlow, P. C. Spurdens, Randy Hays Moss Jan 1995

The Influence Of Pcl 3 On Planarisation And Selectivity Of Inp Regrowth By Atmospheric Pressure Movpe, M. J. Harlow, P. C. Spurdens, Randy Hays Moss

Electrical and Computer Engineering Faculty Research & Creative Works

The introduction of phosphorus trichloride into the AP-MOVPE growth of InP has been found to dramatically improve the regrowth adjacent to mesa structures. By suppressing growth in the [100] direction and enhancing growth in the [311] directions planar regrowth is achieved. Polycrystalline deposits on dielectric masks can also be completely suppressed

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Analysis And Extension Of Model-Based Software Executives, Keith E. Lewis Jan 1995

Analysis And Extension Of Model-Based Software Executives, Keith E. Lewis

Theses and Dissertations

This research developed a comprehensive description of the simulation environment of Architect, a domain-oriented application composition system being developed at the Air Force Institute of Technology to explore new software engineering technologies. The description combines information from several previous research efforts and Architect's source code into a single, comprehensive document. A critical evaluation of the simulation environment was also performed, identifying improvements and modifications that enhance Architecture's application execution capabilities by reducing complexity and execution time. The analysis was then taken one step further and presented extensions to the current simulation environment. The extensions included investigating the feasibility of mixed-mode …

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Concrete Pavement Crack And Seat Performance Overlay Design, Haiming Huang, Thomas D. White Jan 1995

Concrete Pavement Crack And Seat Performance Overlay Design, Haiming Huang, Thomas D. White

JTRP Technical Reports

The objective of this study is to develop guidelines and criteria for design and construction of overlays on cracked and seated concrete pavements. The main factors which are investigated in this study include number of the seated roller pass, weight of seating roller pass, weight of seating roller, thickness of overlay, fiber content and fiber layer location. Eleven test sections were constructed on I-65 and twenty two test sections were constructed on US-31. An extensive investigation was conducted involving both field and laboratory testing. Field investigations included pavement condition survey and non destructive testing (NDT) of the pavements using FWD …

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A Decision Support System For Real-Time Snow And Ice Control, Hjalmar James Miedema, J. R. Wright Jan 1995

A Decision Support System For Real-Time Snow And Ice Control, Hjalmar James Miedema, J. R. Wright

JTRP Technical Reports

Effective real-time snow and ice control operations require a timely initial call-out. A timely initial call-out is one that mobilizes the workforce slightly prior to the onset of hazardous road conditions. In order to estimate the onset of hazardous road conditions, the snow and ice control decision makers use available physical and meteorological information. New technologies are developed that could provide better information, thereby improving the ability to make timely initial call-outs. A systematic methodology for evaluating the benefit of additional information used in snow and ice control initiation is presented. The purposed methodology compares reduction in the direct and …

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An Evaluation Of Lane Closure Strategies For Interstate Work Zones, Raktim Pal, Kumares C. Sinha Jan 1995

An Evaluation Of Lane Closure Strategies For Interstate Work Zones, Raktim Pal, Kumares C. Sinha

JTRP Technical Reports

A systematic procedure was developed in the present study that can be used to make a decision regarding the appropriate lane closure strategy at a particular interstate work zone. Four criteria were identified which influence such a decision, namely user travel time and vehicle operating cost, traffic control cost, safety, and contractors’ convenience. The influences of these criteria were aggregated using the Analytic Hierarchy Approach. The procedure developed in the present study is systematic in nature, simple to use and sensitive to the policy adopted by a transportation agency. A computer program, LANECLOSE, was developed which can be readily used …

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Asphalt Mix Design And Performance, Shakor Ramat Badaruddin, Thomas D. White Jan 1995

Asphalt Mix Design And Performance, Shakor Ramat Badaruddin, Thomas D. White

JTRP Technical Reports

Premature flexible pavement distress became a major concern in Indiana. As a result, a study was conducted investigating the major underlying factors. Pavement sections were investigated based on a factorial study with four factors comprised of climate, truck traffic, pavement base type, and wheel path. The distresses evaluated were rutting, thermal cracking and stripping. All were evaluated against control sections with zero distress. The pavement condition of each section was determined. Laboratory tests of field sample included physical properties, dynamic creep and recompaction. Results of the study indicate that the Asphalt Institute mix design criteria identify an asphalt content that …

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Behavior Of Concrete Bridge Decks And Slabs Reinforced With Epoxy Coated Steel, Hendy Oetih Hasan, J. A. Ramirez Jan 1995

Behavior Of Concrete Bridge Decks And Slabs Reinforced With Epoxy Coated Steel, Hendy Oetih Hasan, J. A. Ramirez

JTRP Technical Reports

Thirty-four slab specimens with splices and transverse steel were tested in the laboratory to evaluate the structural performance of concrete bridge decks reinforced with epoxy-coated steel. Thirty specimens were tested under fatigue loading, and four were tested monotonically. Evaluations were made by comparing the performance of uncoated bar concrete specimens with that of epoxy-coated specimens under service and ultimate load conditions. In addition, a field evaluation of six bridges was conducted to assess the in-service condition of concrete bridge decks reinforced with epoxy-coated steel in Indiana. The laboratory results indicated fewer but wider cracks in specimens with epoxy-coated reinforcement. No …

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Thermal Design Guide For Exterior Walls, Steel In Residential Construction Advisory Group Jan 1995

Thermal Design Guide For Exterior Walls, Steel In Residential Construction Advisory Group

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

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A Diamond Thin Film Flow Sensor, Sacharia Albin, John C. Hagwood, John B. Cooper, David L. Gray, Scott D. Martinson, Michael A. Scott Jan 1995

A Diamond Thin Film Flow Sensor, Sacharia Albin, John C. Hagwood, John B. Cooper, David L. Gray, Scott D. Martinson, Michael A. Scott

Electrical & Computer Engineering Faculty Publications

We present the results of theoretical modeling and experimental testing of a diamond thin film sensor for flow studies. It is shown that the high thermal conductivity of a diamond film can enhance the frequency response of the flow sensor. One-dimensional heat diffusion equation was solved using the finite difference method for determining the frequency response. Two different sensor structures were analyzed: a Ni film on a quartz substrate (Ni/Q) and an intermediate layer of diamond film between the Ni film and quartz substrate (Ni/D/Q). The theoretical model predicts a frequency response for the Ni/D/Q sensor higher than that of …

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Em Interaction Of Handset Antennas And A Human In Personal Communications, Michael A. Jensen, Yahya Rahmat-Samii Jan 1995

Em Interaction Of Handset Antennas And A Human In Personal Communications, Michael A. Jensen, Yahya Rahmat-Samii

Faculty Publications

In personal communications, the electromagnetic interaction between handset-mounted antennas and the nearby biological tissue is a key consideration. This paper presents a thorough investigation of this antenna-tissue interaction using the finite-difference time-domain (FDTD) electromagnetic simulation approach with detailed models of real-life antennas on a transceiver handset. The monopole, side-mounted planar inverted F, top-mounted bent inverted F, and back-mounted planar inverted F antennas are selected as representative examples of external and internal configurations. Detailed models of the human head and hand are implemented to investigate the effects of the tissue location and physical model on the antenna performance. Experimental results are …

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Thermophoretic Sampling Of Coal-Derived Soot Particles During Devolatilization, Jinliang Ma, Thomas H. Fletcher, Brent W. Webb Jan 1995

Thermophoretic Sampling Of Coal-Derived Soot Particles During Devolatilization, Jinliang Ma, Thomas H. Fletcher, Brent W. Webb

Faculty Publications

Thermophoretic sampling of soot particles formed during high-temperature coal devolatilization is performed in order to examine soot particle sizes and shapes. Coal particles are injected along the centerline of a laminar flow flat flame burner, where a fuel-rich methane-air flame is used as a heat source. Volatiles released from the coal particles form a cloud of soot particles at high temperatures in the absence of oxygen. A carbon-coated microscope grid is briefly inserted into the soot cloud, where the temperature gradient between the soot particles and the cold grid surface causes the migration of soot particles and results in deposition. …

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Effects Of Pyrolysis Conditions On Internal Surface Areas And Densities Of Coal Chars Prepared At High Heating Rates In Reactive And Non-Reactive Atmospheres, Thomas K. Gale, Thomas H. Fletcher, Calvin H. Bartholomew Jan 1995

Effects Of Pyrolysis Conditions On Internal Surface Areas And Densities Of Coal Chars Prepared At High Heating Rates In Reactive And Non-Reactive Atmospheres, Thomas K. Gale, Thomas H. Fletcher, Calvin H. Bartholomew

Faculty Publications

Concern about comparability and validity of different methods for producing coal chars for reactivity experiments has led to research on the effect of devolatilization conditions on the char physical and chemical structure. Particle diameter and porosity changes during devolatilization significantly affect char oxidation rates. In particular, physical properties of chars prepared in drop tube reactors differ greatly from chars prepared in fiat flame burner experiments. Recent data indicate that the presence of oxygen in the gas atmosphere has no effect on swelling until char oxidation has begun. The present research concentrates on the effects of heating rate, particle temperature and …

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Effects Of Large Aspect Ratios And Fluctuations On Hard X-Ray-Detection In Lower Hybrid Driven Divertor Tokamaks, Linda L. Vahala, George Vahala, Paul Bonoli Jan 1995

Effects Of Large Aspect Ratios And Fluctuations On Hard X-Ray-Detection In Lower Hybrid Driven Divertor Tokamaks, Linda L. Vahala, George Vahala, Paul Bonoli

Electrical & Computer Engineering Faculty Publications

It is shown that lower hybrid wave scattering from fluctuations plays a critical role in large aspect ratio divertor plasmas even through the edge density fluctuation levels are only at 1%. This is seen in the theoretically calculated electron power-density profiles which can be directly correlated to the standard experimental chordal hard x-ray profiles. It thus seems that fluctuation effects must be included in determining rf current-density profiles.

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A Comparative Study Of The Perceived Educational Needs Of Iowa Merged Area Vii Manufacturers And Iowa Technical Educators, David D. Bradney Jan 1995

A Comparative Study Of The Perceived Educational Needs Of Iowa Merged Area Vii Manufacturers And Iowa Technical Educators, David D. Bradney

Dissertations and Theses @ UNI

This research was a descriptive pilot study that compared the perceptions of Iowa Merged Area VII manufacturers and Iowa technical educators regarding technical curricula, occupational skill certification, and drafting practices as these relate to Associate Degree programs in Mechanical Drafting and Design Technology. The problem was to determine what should be taught in two year technical curricula in Mechanical Drafting and Design Technology. The purpose of the study was to compare the perceived educational needs of Iowa Merged Area VII manufacturers and Iowa technical educators regarding the content of Mechanical Drafting and Design Technology curricula. The populations used for this …

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Information Theoretic Mask Analysis Of Rainfall Time Series Data, Martin Zwick, Hui Shu, Roy Koch Jan 1995

Information Theoretic Mask Analysis Of Rainfall Time Series Data, Martin Zwick, Hui Shu, Roy Koch

Complex Systems Faculty Publications and Presentations

This study explores an information-theoretic/log-linear approach to multivariate time series analysis. The method is applied to daily rainfall data(4 sites, 9 years), originally quantitative but here treated as dichotomous. The analysis ascertains which lagged variables are most predictive of future rainfall and how season can be optimally defined as an auxiliary predicting parameter. Call the rainfall variables at the four sites A...D, and collectively, Z, the lagged site variables at t-1, E,,,H, at t-2, I...L, etc. and the seasonal parameter, S. The best model, reducing the Shannon uncertainty, u(Z), by 22%. is HGFSJK Z, where the independent variables, H through …

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Variance And Uncertainty Measures Of Population Diversity Dynamics, Mark A. Bedau, Martin Zwick, Alan Bahm Jan 1995

Variance And Uncertainty Measures Of Population Diversity Dynamics, Mark A. Bedau, Martin Zwick, Alan Bahm

Complex Systems Faculty Publications and Presentations

We define variance and uncertainty measures of population diversity. Both measures have precise decompositions that we can exploit in analysis of evolutionary dynamics. We discuss how these measures are related and how they can be observed in artificial and natural evolving systems.

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Kentucky Traffic Accident Facts 1995 Report, Kentucky Transportation Center, Kentucky State Police Jan 1995

Kentucky Traffic Accident Facts 1995 Report, Kentucky Transportation Center, Kentucky State Police

Kentucky Transportation Center Research Report

No abstract provided.

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A User’S Guide For By Product And Discarded Material Utilization In Highway Construction And Maintenance, Kamyar C. Mahboub, David Q. Hunsucker Jan 1995

A User’S Guide For By Product And Discarded Material Utilization In Highway Construction And Maintenance, Kamyar C. Mahboub, David Q. Hunsucker

Kentucky Transportation Center Research Report

This report presents a user's guide for an expert decision-making system that utilizes findings of an extensive literature search and review conducted as part of this study. The literature search and review were conducted to determine current attitudes and document available technical data relative to the use of recyclable and recoverable materials in highway construction and maintenance activities. Specifically, the literature search focused upon the engineering, economic, and performance aspects of using recyclable and recoverable materials in highway construction and maintenance projects. The effort centered upon asphalt and Portland cement concrete pavement recycling, discarded tire recycling, reuse of paint removal …

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